Rock drill bit



March 30, 1954 J. B. BAKER 2,573,715

ROCK DRILL BIT Filed June 2, 1950 2 Sheets-Sheet l I INVENTORZ JOHN BC BAKER AT TORNEYS.

g di /km flue M,

March 30, 1954 J. B. BAKER 2,673,715

' ROCK DRILL BIT Filed June 2, 1950 2 Sheets-Sheet 2 FIG. 9. FIG. IO.

INVENTOR. /6 M JOHN B. BAKER AT TORN EYS.

Patented Mar. 30, 1954 ROCK DRILL BIT John B. Baker, Canton, Ohio, assignor to The Timken Roller Bearing Company, Canton, Ohio,

a corporation of Ohio Application June 2, 1950, Serial No, 165,673

This invention relates to rock drill bits and is more particularly directed to a method of securing a drill rod to the bit for preventing relative rotation therebetween.

The principal object of the invention is to provide means for quickly securing one-use rock drill bits to the drill rod in a rapid and economical manner and which can be easilydisassembled.

Another object of the invention is to provide means for quickly securing a rock drill bit to the drill rod for preventing relative rotation between the parts.

The invention consists in the provision of a drill bit having cutting edges on one face and a boss on the other side thereof over which a tubular member is fitted for receiving a drill rod having the same cross section as the boss, the tubular member being secured to the drill bit, the boss having projections thereon penetrating the end of the drill rod for spreading the rod to hold the bit assembled thereon and for preventing relative rotation between the rod and the drill bit during operation of the drill bit assembly.

In the drawings:

Fig. 1 is a longitudinal sectional view of a drill bit assembly incorporating the invention,

Fig. 2 is a side elevational view of the drill bit,

Fig. 3 is a plan view of the non-cutting face of the drill bit.

Fig. 4 is a longitudinal sectional view of a modified form of the invention,

Fig. 5 is a side elevational view of the bit shown in Fig. 4,

Fig. 6 is a vertical sectional view of the bit shown in Fig. 5,

Fig. '7 is a plan view of the non-cutting face of a modified drill bit,

Fig. 8 is a longitudinal sectional view of another form of the invention,

Fig. 9 is a side elevational view of the drill bit shown in Fig. 8,

Fig. 10 is a vertical sectional view of the drill bit shown in Fig. 9,

Fig. 11 is a plan view of the non-cutting face of the drill bit shown in Fig. 10,

Fig. 12 is a longitudinal sectional view of another form of the invention,

Fig. 13 is a side elevational view thereof,

Fig. 14 is a longitudinal sectional View of the drill bit shown in Fig. 13; and

Fig. 15 is a plan view of the non-cutting face of the drill bit shown in Fig. 14.

The invention is embodied in the structure set 2 Claims. (Cl. 25563) 2 forth in Figs. 1 through 3 of the drawings in which the numeral I designates a drill bit rod of comparatively soft steel. This rod is inserted in a sleeve 2 made from low cost tubing secured to the drill bit body 3. The drill bit body has cutting edges 4 formed on one face thereof, the

other face having a boss 5 thereon with a plurality of outwardly projecting conical points on the outer side thereof. The sleeve 2 snugly fits about the boss 5 and is secured to the drill bit body 3 by brazing or other suitable means. The drill rod is inserted in the sleeve 2 and the conical points are then embedded in the end of rod l as the bit is used. The embedding action spreads the end of the rod so that it may firmly frictionally engage the sleeve. Relative rotation between the drill bit and the rod is therefore prevented by reason of the friction between the drill rod and sleeve and the interengagement of the points and the drill rod. The spreading of the rod by the conical points prevents accidental separation of the parts. When it is desired to remove the drill bit from the rod, it is tapped with a hammer, thus effecting separation of the parts.

A modified form of the invention is shown in Figs. 4 through '7, in which I is a drill rod made from a soft steel received in sleeve 8 secured to the drill bit 9, the sleeve being made from low cost tubing and brazed or otherwise secured thereto. The drill bit is provided with cutting edges to on one face thereof, the opposite face having a boss II that is received within the sleeve 8. The boss is made with a concave end, as shown in Figs. 4 and 6, the outermost face having a plurality of radial serrations l2 thereon. The function of these serrations in connection with the drill rod is identical with the conical points described above. The drill bit is removed from the rod by tapping with a hammer, as set forth above.

A variation of the structure shown in Figs. 4 through 7 is described in connection with Figs. 8 through 11. These parts bear the same reference numerals as in the previously described structure of Figs. 4 through 7. A boss II or the like, shown in Figs. 8 through 11, is formed with a flat face having radial serrations thereon acting on the drill rod in the same manner as in the previously described form of the invention.

Another modified form of the invention is shown in Figs. 12 through 15 in which the numeral l3 designates a drill bit rod made of soft steel. This rod is received in a sleeve l4 made from low cost tubular stock and hasa polygonal 3 bore therein, the rod l3 being provided with a similar section. The sleeve I4 is secured to the drill bit l5 by brazing .or other suitable means. The drill bit has cutting edges 16 on one side thereof and a boss I! on the opposite side has a polygonal section similar to that of the bore in sleeve l4 and fits in the sleeve bore. The boss has outwardly directed conical points I8 thereon that are embedded in the end of the drill rod 13. The function of the conical points is identical to the points or serrations described above which, in cooperation with the polygonal rod, prevents relative rotation of the drill bit and rod. The drill bit and the rod may be separated by tapping the bit with a hammer. The bores of the sleeves shown in Figs. 1 through 11 may be made polygonal if so desired, and when so made, may or may not employ serrations or conical projections. The end of the drill rod may have to be machined after each use before it can be reused, thus prolonging the life thereof. If the end of the drill becomes damaged, it may be cut oif square prior to reuse, thus further extending its usefulness.

What I claim is:

1. A rock drill bit assembly comprising a drill bit body formed from relatively non-deformable material and having a plurality of cutting edges on one side thereof and a boss of non-deformable material on the other side, a sleeve secured to said drill bit body and received about said boss, a drill rod in said sleeve and formed from relatively deformable material; and a plurality of radial serrations also formed of the non-deformable material and disposed on the outer face of said boss to be embedded in said rod for spreading same to cause said drill rod to fit within said sleeve in frictional engagement, said serrations and the frictional engagement preventing relative rotation of said drill bit and said rod.

2. A rock drill bit assembly comprising a drill bit body formed from relatively non-deformable material and having a plurality of cutting edges on one face thereof and a boss of non-deformable material on the other face, said boss having a concave depression therein, a sleeve surrounding said boss and secured to said drill bit body and having a bore therein of the same cross section as said boss, a drill rod formed from relatively deformable material, said drill rod being disposed .in said sleeve and having a cross section of the same shape as said boss and the bore in said sleeve; and a. plurality of radial serrations of non-deformable material formed in the concave depression of said boss to be forced into said drill rod to expand said drill rod for holding same in frictional engagement with said sleeve and for preventing relative rotation of said drill bit and said rod.

JOHN B. BAKER.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 764,943 Guy July 12, 1904 853,062 Clark May '7, 1907 1,136,987 Wakfer Apr. 27, 1915 2,085,941 Arnold July 6, 1937 2,354,656 Annesley Aug. 1, 1944 2,441,188 Earhart May 11, 1948 2,454,771 Carr Nov. 30, 1948 

